Hydrogen induced vibrational and electronic transitions in chemical vapor deposited diamond identified by isotopic substitution

Homoepitaxial diamond films grown by chemical vapor deposotion from high12C and high13C containing gases have been studied by Fourier transform infrared spectroscopy. A sharp absorption band observed at 3123cmhighminus1 is attributed to a CH vibrational absorption. It resembles the previously observed 3107cmhighminus1 absorption band in natural diamond. Isotopic replacement of carbon, hydrogen, and nitrogen by high13C,high2H, and high15N reveals, that a CH center without nitrogen participation is responsible for this new absorption. Furthermore, new hydrogen related electronic transitions have been observed around 7300cmhighminus1. These lines shift to higher energies in high13C crystals, in accordance with the increase of the electronic band gap.